Extension-table slide



July 9, 1929. H. H. DREW 1.720.320

- EXTENSION TABLE SLIDE Filed June 6, 1927 Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

HERBERT H. DREW, OF WATERTOWN, WISCONSIN, ASSIGNOR TO WAT'ERTOWN TABLE SLIDE 00., OF WATERTOWN, WISCONSIN.

EXTENSION-TABLE SLIDE.

Application filed June 6', 1927. Serial No. 196,856.

This invention pertains to improvements in extension table slides, and more particularly to a mechanism for equalizing the movement of the slides.

Primarily the invention has for its object to provide an improved structure of the foregoing character which is simple, inexpensive, efficient and durable, and which insures proper alinement and operative engagement between the movable parts under any and all conditions.

More specifically the invention pertains to an improvement in what is termed the rack and pinion type of equalizer, wherein considerable diiliculty and objections have been encountered in providing and maintaining the proper alinement between the racks carried by the movable slides and pinions secured to the stationary slides. The present invention provides a self-adjusting pinion which will readily accommodate itself to any variation between the racks, thus rendering the same self-centering and resulting in the reduction of bind, wear, friction, noise of oporation, and cost of manufacture. In addition to the foregoing advantages, numerous others will become apparent as the description proceeds.

With the above and other objects in View, which will appear as the description proceeds, the invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claims.

In accompanying drawings is illustrated one complete example of the physical em bodiment of the present invention constructed according to the best mode so far devised for the practical application of the principles thereof.

Figure 1 is a fragmentary plan View of a conventional table slide set with the invention attached thereto.

Figure 2 is a longitudinal section taken on the line 2--2 of Figure 1, and

Figure 3 is a transverse section taken on the line 33 of Figure 1.

Referring now more particularly to the accompanying drawings, wherein the invention is shown attached to a set of extension table slides of conventional structure, the numeral 1 designates a fixed center rail adapted to be secured to a pedestal, or other form of suitable support, in the usual manner.

Positioned upon opposite sides of the fixed rail 1 is a pair of slidable rails 2 which are secured to the respective end table sections in a manner Well known to those skilled in the art.

Both the fixed rail 1 and the sliding rails 2 are provided with dove-tailed grooves 3 in their abutting faces, which grooves receive the guide members 4 that serve as slidable conlnections between the fixed and movable rai s. As pointed out in the objects, the present invention consists primarily in an improvement in the equalizing means employed, and therefore it will be understood that the specific structure of the slides form no part of the present invention other than in the combinationsdefined by the claims.

The equalizing means employed for equalizing the movement of the sliding rails 2 is of the rack and pinion type, and embodies a pair of racks 5 secured horizontally to faces of the sliding rails 2 with their teeth projecting towards the fixed rail 1. A bracket comprising a strap 7 is provided with offset ends 8 and 9 respectively, the end 8 being pivotally secured to the face of the fixed rail 1 by means of the screw 10. The opposite end 9 of the bracket 7 is provided with an elongated slot 11 for thereception of the screw 12, which cooperates with the screw 10 to secure the bracket 7 to the fixed rail 1, and at the same time permit oscillatory movement of the bracket. Carried by the bracket 7 intermediate its ofi'set ends and positioned between the bracket and the face of the fixed rail 1, is the pinion 13 which extends over the slide rails 2 and engages the opposed racks 5.

As previously explained, the generic principle of the rack and gear type of equalizer is well known in theart, but considerable difficulty has been encountered in maintaining proper alinement and operative engagement between the racks and pinion employed, due

ap e d glams.

-to the fact that the conventional slides are manufactured from wood, which is subject to moreor less --wairpiiig with changes of climatiecoiiditions; and, further, dueto'wear in the connections between the slides, the same are inclined, ,tobecoine loose with continued use wlii ch results in 'dialinemcnt bctween the racks and pinion.

It has also been found that veryclose v and precise machine work is required in order to obtain a proper engagement between the;

racks and pinions which would permit of essential -easy and quiet operation. Obvi- 'ous'ly any -di's'aline nent between the racks and pinion-wouldresult in considerable friction and wear, requiring additional effort to noise ofop'eration; and compensating for any warp-or twist in the rail sect-ions.

A'f-urtheradvantage of this arrangement resides in the fact that strainon the pinion is perfectlyequali-Zed, which reduces wear uponthe parts and increases their life. Alsm'becauseof the compensating feature ot' the presentstruct'ure; precise machine I work is unnecessary-and slight defects in workmanshipw-ill' not seriously affectthe ease of o'p'enationwi i r Furtherfthe present invention materially improvesthe appearance of the equalizing mechanism in'-'-that" the 'bi'acket covers the greater portioa-oftlie pinion, which also protects the sam'ei against .disalinement or damage during shipping. v

"While one speoific'inetliod of inovably seeuring'th'e pinion '13' tothe fixed rail has been illustrated and described in: considerable detail;- it is obvious that Various means may. be; employed 5 for accomplishing the same-result. Therefore; the present invention' is on-ly'to 'beilimitedto the scope of the I claim:

1. An extension table slide comprising a fixed rail, a pair of movable side rails connected with and slidably guided oii.op1 ')osite sidesofthe fixed rail, opposed longitudinal racks secured horizontally to the movable rai.ls,,and alaterallyfloating pinion secured tothe fixed rails and engaging the racks earried by said movable rails and means for guiding said pinion laterally with respect to said racks.

2. An extension table comprising a fixed rail,-apairof movable side rails connected with and slidably guided on opposite sides of the fixed rail, opposed longitlnilinal raclzs secured horizontally to the movable rails, a bracket piv'otally secured to said fixed rails. and-a pinion carried by said bracket for engagement witlr the racks carried by said. movable rails.

I An extension table coinpnising a fixed rail, a pairo'li movable side rails connected with and slidably guided on opposite sides of the fixed rail, opposed longitudinal racks secured horizontally to the movable rails, a bracket having one end secured tothe fixed rail and its opposite end. inovably attached to said fixed rail, and a pinion carried: by said bracket intern'iediatc its endsdor engaging the racks carried by said movable rails.

4. An extension table comprising a fixed rail, a pair of movable side rails connected with and slidably guided on opposite sides ot-the fixed rail, opposed longitiulinal racks secured horizontally to ihenmvable rails, a bracket having offset ends, means for pivotally attaching one of said ends to sai d fixed rail, means for movable securing the opposite end to said fixed rail, and a pinion carried by said bracket intermediate the blzlt'litt' and the fixed rail for engagement with the racks carried by said movable rails.

'In testimony that I'claini the foregoing I have hereunto set my hand at lVateriown, in the county of Jefferson and State of Visconsin.

HERBERT- H. DREW] 

